Artificial silk having subdued luster



Patented Apr. 20, 1937 PATENT OFFICE ARTIFICIAL SILK HAVING SUBDUED LUSTER- Emil Kline, Buffalo, N. Y., assignor, bymesne assignments, to E. I. du Pont de'Nemours & Company, Wilmington, Del., a corporation of Delaware No Drawing. Application March 22, 1935, Serial No. 12,440. Renewed August 29, 1936 3 Claims.

This invention relates to cellulosic structures, such as films, threads, fibers, sheets, filaments, caps, tubing and the like, of either the regenerated cellulose or cellulose derivative type.

I More particularly, this invention relates to cellulosic structures of the type just mentioned having subdued or low luster and/or being more or less opaque.

In the ordinary methods for producing cellulosic structures, such as filaments, threads, films, caps, tubing, etc., from viscose, cuprammonium cellulose, nitrocellulose, cellulose acetate and other cellulosic solutions (without the addition of low luster-inducing agents to the solutions) the products are transparent or transluscent and/or very highly lustrous when compared to ordinary cotton fibers or natural silk. For many purposes the brilliant sheen and luster are not desirable and thus a limitation of the uses of the material results. Recently, methods have been proposed for producing cellulosic structures having a low or subdued luster. Certain of the suggested methods in connection with the production of artificial thread contemplated incorporating substances, such as inorganic pigments, mineral oils, certain fats, waxes, etc., in the spinning solution and spinning the resultant solution.

Other methods proposed spinning solutions in 30 which materials, such as benzene, monochlorobenzene, aniline and other organic liquid substances, were incorporated, and these substances were either automatically removed during the process of producing the thread or deliberately 35 removed from the formed thread by a solvent or chemical action, vacuum or other treatment.

In my application Serial No. 607,214 the use of chlorinated diphenyls for producing delustered and/or opaque cellulosic structures is described. The chlorinated diphenyls described in my copending application, and also those which have been used prior to the instant invention, were all only partially chlorinated diphenyls, the maximum chlorine content being 69%, corresponding to approximately 9.0 atoms per molecule.

I have now found that completely chlorinated diphenyl, i. e. deca chlorodiphenyl, has a distinctively greater delustering power than any of the other chlorinated diphenyls, or mixtures thereof, used prior to this invention for delustering purposes. For example, I have found that deca chlorodiphenyl is 2 to 3 times as efiective a delustrant on a weight basis as a mixture of chlorodiphenyls which has an average chlorine content corresponding to about 9.0 atoms per molecule. Completing the chlorination of the diphenyl molecule would be expected to increase the delustering power more or less in proportion to the increase in chlorine percentage in the molecule. However, the increase in the delustering power of deca chlorodiphenyl is, as previously mentioned, 200 to 300 per cent. over the most eiiective prior usedchlorinated diphenyl, and this increase is surprising and unobvious.

It is, therefore, an object of this invention to provide a method of producing artificial thread characterized by a subdued or low luster and/or opacity.

Another object of this invention is to provide a spinning solution which will produce an artificial thread characterized by a subdued or low luster and/or opacity.

A still further object of this invention is to provide an artificial thread characterized by a subdued or low luster and/or opacity.

Other objects of the invention will become apparent from the following description and appended claims.

In accordance With the principles of the instant invention there are provided cellulosic structures, such as filaments, threads, fabrics, sheets, films, caps, tubing and the like, having a subdued or low luster and/ or being more or less opaque. These desiderata are secured, according to the instant invention by incorporating deca chlorodiphenyl in the solution from which the structure is produced.

Deca chlorodiphenyl remains substantially permanently in the finished product and can be substantially uniformly distributed and incorporated throughout the mass of said product. It possesses a sufiiciently low vapor pressure and is sufficiently inert to resist change or removal from the structure in the ordinary process of making and finishing the structure during its manufacture. 'It also effectively resists removal or change during any of the usual processes to which the finished structure may be subjected, such as boiling off, dyeing, bleaching, ironing, etc. Still further, deca chlorodiphenyl is relatively stable to light and does not degrade the product either during the course of the manufacture thereof or during its use. Regenerated cellulose threads containing deca chlorodiphenyl may be bleached in the light without loss in strength and may be exposed to light in their moist or dry condition without deterioration.

The quantity of deca chlorodiphenyl used may vary within wide limits, depending chiefly upon the opaquing and/or luster desired in the finished product, as well as upon the particle size. For artificial thread I have found that satisfactory results are secured when the final thread 5 contains from approximately .1% to approximately 12.5% by weight of the deca chlorodiphenyl. Thus, in the production of artificial thread, for example, produced from viscose containing approximately 7% cellulose, satisfactory 10 results are secured when the viscose solution contains from approximately 0.01% to approximately 1.0% deca chlorodiphenyl. For films, tubing, caps, etc., the deca chlorodiphenyl content may be greater than that of artificial thread if desired and satisfactory results are secured if these products contain up to approximately 40% by weight of deca chlorodiphenyl. Thus, in the production of films, tubing, caps, etc., from viscose solutions, concentrations of deca chloro- 20 diphenyl up to 5.0% or more based on the viscose solution containing 7% cellulose may be used.

There are two primary grades of low luster yarn, which may be referred to as semi-dull and full-dull luster. Satisfactory semi-dull and fulldull yarn can be secured if the yarn contains approximately 1.25% and approximately 5.0% by weight of deca chlorodiphenyl respectively. Specifically, a viscose solution containing 7% cellulose will produce a rayon having a desirable semi-dull luster, if 0.1% of deca chlorodiphenyl is incorporated therein, while a concentration of 0.4% deca chlorodiphenyl or higher will produce a yarn having a very dull mat appearance.

The particle size of the deca chlorodiphenyl is of extreme significance from the. point of view of the low luster effects produced. It is to be understood that here I am not concerned with the smallest possible particle size nor that particle size necessary for optimum spinning. There is an optimum particle size for deca chlorodiphenyl which aids in producing maximum low luster effects. This particle size is obviously sumciently small to permit good spinning in the manufacture of artificial thread and to prevent any serious adverse effect on the strength and quality of the thread. The optimum particle size of the deca chlorodiphenyl is one to two (1-2) microns diameter.

The deca chlorodiphenyl may be added to the. 50 cellulosic solution at any stage in the course of the manufacture thereof or after the preparation of the solution and prior to spinning or casting. It may be incorporated, for example, in a viscose solution by introducing it at that stage in 55 the. process where the cellulose xanthate is converted to the viscose solution. In this embodiment the deca chlorodiphenyl may be either added to the caustic soda solution or to the xanthate to which the caustic soda solution is 60 added.

If the particle size is satisfactory, the deca chlorodiphenyl is added as hereinbefore mentioned. If the original particle size of the deca chlorodiphenyl is not satisfactory, it is adjusted 65 to the desired particle size by any of the wellknown methods, such as grinding in a colloid mill or pebble mill or in the form of a suspension prepared with or without the assistance of suitable dispersing agents or protective colloids, such as soaps, sulphonated oils, alkyl naphthalene sulphonic acid salts, sodium caseinate, etc.

Though the preferred embodiment of the invention contemplates the addition of deca chlorodiphenyl alone for the purpose desired, nevertheless, the invention is not restricted thereto. The deca chlorodiphenyl may be, in accordance with the principles of this invention, used conjointly with any other suitable low luster and/or opacifying agent, such as mineral oils, waxes, organic solvents, such as benzene, etc., or inorganic pigments, such as titanium oxide, zinc sulphide, barium sulphate, etc. It may also be used together with other organic pigments, such as ethylene glycol di-beta-naphthyl ether, etc. The relative amounts of deca chlorodiphenyl and the other delusterant may vary over the range in which these materials are commonly used by themselves, the exact amounts depending upon the particular effect desired.

In order to more clearly describe the invention, the following specific examples are given, it being understood that these examples are not intended to be limitative of the invention but are merely for the purpose of illustrating several specific embodiments which have been found to produce satisfactory results:

Example I .-1 pound of deca chlorodiphenyl is ground as a water slurry to an average particle size of 1 micron diameter by means of a ball mill or colloid mill with the aid of some wetting agent, for example, sodium caseinate. The water slurry is thoroughly incorporated in 1,000 pounds of a viscose solution containing 7% cellulose. The viscose solution is then filtered, ripened and spun in the usual way. The yarn produced by this procedure is characterized by a pleasing, semidull appearance.

Example IL- l pounds of deca chlorodiphenyl which has been ground in a water slurry to a particle size of about 1 micron diameter, as set forth in Example I, is thoroughly incorporated in 1,000 pounds of a viscose solution containing 7% cellulose. The viscose is filtered, ripened and spun in the usual way. The yarn produced by this procedure is characterized by a pleasing, dull appearance.

Though the specific examples describe that embodiment of the invention which relates to the production of viscose rayon, the invention is not restricted thereto. It is equally applicable to the production of artificial thread from other cellulosic solutions, such as cellulose acetate, cellulose nitrate, cuprammonium cellulose, etc. Also, the invention is applicable to the production of films, sheets, tubing, caps and bands produced from any of the aforementioned solutions.

Since it is obvious that various changes and modifications may be made in the above description without departing from the nature or spirit thereof, this invention is not restricted thereto except as set forth in the appended claims.

I claim:

1. Rayon containing approximately 1.25%, by weight, of finely divided deca. chlorodiphenyl uniformly distributed throughout the mass thereof to impart a subdued or low luster and/ or opacity to the product.

2. Rayon containing not more than approximately 5.0%, by weight, of finely divided deca chlorodiphenyl uniformly distributed throughout the mass thereof to impart a subdued or low luster and/or opacity to the product.

3. Rayon containing from approximately 1.25% to not more than approximately 5.0%, by weight, of finely divided deca chlorodiphenyl uniformly distributed throughout the mass thereof to impart a subdued or low luster and/or opacity to the product.

EMIL KLIN'E. 

